This invention relates to an iris image pickup apparatus for picking up an iris image used for individual identification, etc., of a security system and in particular to an iris image pickup apparatus suited for efficiently picking up a good iris image that can be used for iris authentication processing.
If a subject wears glasses, illumination light glares on the picked-up image of the iris used for authentication processing and the percentage of the illumination light image overlapping the iris image is raised, lowering the authentication rate of the iris. Then, a conventional iris image pickup apparatus in a related art is designed for preventing such lowering the authentication rate of the iris.
For example, as described in Japanese Patent Publication No. H10-5195, when illumination light for picking up an iris image is applied to an eyeball, whether the iris image is good or NG is determined based on the amount of illumination reflected light (when the subject wears glasses, the reflected light amount is much) and if the iris image is determined a bad image (the reflected light amount is much and the illumination light glares on the glasses), illumination is applied to the eyeball from another incidence angle and again an image of the eyeball is picked up as the illumination light is applied, and whether the image is good or NG is determined in a similar manner. After this, the procedure of applying the illumination light to the eyeball at various incidence angles and determining whether the iris image is good or NG is repeated until a good image is provided (an image with less reflected light amount is provided).
In the conventional iris image pickup apparatus described above, the illumination incidence angle is changed one after another and picking up an image is repeated until a good iris image with no illumination light glaring on the iris part is provided, and thus it may take a long time until a good iris image is provided; this is a problem. To prevent the illumination light from glaring on the iris part, the interval from the camera to the lighting fixture must be taken wide; this is also a problem.
Further, with the conventional iris image pickup apparatus, when an image is picked up is not known and thus the probability that an iris image pickup failure will occur due to a blink of the subject is high, and there is a possibility that the whole time taken for authentication may be prolonged as the number of times an image is picked up is increased; this is a problem.